Anti-entanglement propeller for underwater operation

ABSTRACT

A propeller for attachment to a rotatable output shaft of a submersible motor includes a hub having a first end, and an opposite second end, an outer curved surface, at least two blades extending radially outward from the outer curved surface and a central axial bore for receipt of the output shaft therethrough. The hub includes an arrangement of discharge channels extending between the first and second ends to allow waterflow and debris (e.g., grass, weeds and other stringy items) to pass through the hub and exit the second end without becoming entangled around the base of the motor output shaft.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to propellers and, more particularly, to a propeller for attachment to an output shaft of a submersible motor, such as on a self-contained submersible pool vacuum head, and wherein the hub of the propeller is specifically structured to discourage debris, such as grass and weeds from becoming entangled around the base of the output shaft of the motor.

Description of the Related Art

Submersible motors, and particularly electrically powered submersible motors include a watertight motor housing with an output shaft that extends from an end of the waterproof housing. A propeller is mounted to the output shaft which drives rotation of the propeller upon operation of the motor, thereby creating a force of thrust as water is moved by the blades of the propeller. An example of a submersible electric motor that drives rotation of a propeller can be found in U.S. Pat. No. 5,768,734 directed to a self-contained swimming pool vacuum.

A common problem encountered with submersible motors having an output shaft for driving rotation of a propeller is the collection of debris, such as grass, weeds and other stringy items around the base of the output shaft (i.e., adjacent to where the output shaft exits the motor housing) and between the end of the motor housing and the hub of the propeller. Accumulation of debris about the output shaft of the motor can interfere with the proper operation of the motor and propeller, and particularly the ability to create a sufficient force of thrust. Moreover, excessive debris that accumulates around the shaft can cause fowling of the propeller and obstruction to rotation of the propeller and driveshaft. Not only does this result in poor operation of the motor and propeller to create a sufficient force of thrust, but this can also create excessive strain on the motor which will shorten the useful life of the electric motor. The reason debris such as grass and weeds gets entangled around the output shaft is because the hub of the propeller, being spaced very close to the end of the motor housing, blocks the passage of the debris that may be pulled in between the hub and the motor housing. More specifically, one end of the hub is maintained in close, spaced relation to the end of the motor housing where the output shaft exits the motor housing. Any debris that enters this area between the hub and the motor housing can get trapped between the hub and motor housing and eventually gets wrapped around the rotating output shaft. As debris wraps around the output shaft, a strain is put on the motor and effective rotation of the propeller and output shaft can be significantly diminished.

Accordingly, there remains a need for an improved propeller design that allows for debris, such as grass, weeds and other stringy items, to exit through the hub of the propeller prior to becoming entangled about the output shaft of the electric motor.

SUMMARY OF THE INVENTION

The present invention is directed to a propeller that is specifically designed and structured for attachment to an output shaft of a submersible motor. More particularly, the propeller of the present invention is intended for attachment to the output shaft of a submersible electric motor such as, for example, an electric motor used in a submersible self-contained swimming pool vacuum head. The propeller includes a hub having a first end and an opposite second end. The hub further includes an outer curved surface which, in a preferred embodiment, is a cylindrical surface. The propeller includes at least two blades that are spaced apart from one another and extend radially outward from the outer curved surface of the hub. The blades are positioned, shaped and designed to provide a propeller pitch that achieves a desired thrust when rotated at various operating speeds under water. The hub further includes a central axial bore for receipt of the output shaft of the motor therethrough. A washer and nut, or other well-known fastener is used to secure the propeller on the shaft which may be threaded to receive the nut or other screw fastener.

The hub of the propeller of the present invention is specifically designed to include an arrangement of discharge channels about the entire circumference of the hub, extending between the first and second ends. More specifically, the discharge channels are open at the first and second ends of the hub providing an unobstructed passage therethrough. In operation (i.e., underwater rotation of the propeller), the discharge channels allow waterflow and debris (e.g., grass, weeds and other stringy items) to pass through the hub and exit the second end without becoming entangled around the base of the output shaft between the motor housing and the propeller hub. This avoids obstruction to the rotation of the propeller, which is driven by the output shaft of the motor, thereby allowing the motor and propeller to operate more efficiently while creating the desired thrust force without strain on the motor.

These and other objects, features and advantages of the present invention will become clearer when the drawings as well as the detailed description are taken into consideration.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a top perspective view of a self-contained submersible swimming pool vacuum head including a housing, a thrust channel formed through the housing and a catch bag removably secured to a top discharge opening of the vacuum housing, and wherein the propeller of the present invention is shown on the output shaft of an electric motor within the thrust channel of the vacuum housing;

FIG. 2 is a top, side perspective view shown in partial cross-section and illustrating the electric motor and the propeller of the present invention within the thrust channel of the submersible swimming pool vacuum head housing, and wherein the arrows indicate a direction of flow of water through the thrust channel of the vacuum head housing as the electric motor drives rotation of the propeller;

FIG. 3 is an exploded perspective view, shown in partial cross-section, showing the electric motor mounted within the thrust channel of the submersible swimming pool vacuum head housing and the propeller of the present invention separated from the output shaft of the electric motor;

FIG. 4 is a top plan view showing the propeller of the present invention mounted on the output shaft of the electric motor within the thrust channel of the swimming pool vacuum head housing; and

FIG. 5 is an isolated view, in partial cross-section, showing the hub of the propeller secured to the output shaft of the electric motor.

Like reference numerals refer to like parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the several views of the drawings, and initially FIG. 1, a self-contained submersible swimming pool vacuum head 100 is shown in operation being moved along the bottom surface of a swimming pool to pick up dirt and debris such as dirt, sand, leaves, grass, weeds, etc. An example of the self-contained submersible swimming pool vacuum is shown and fully disclosed in U.S. Pat. No. 5,768,734 the contents of which are fully incorporated herein by reference. As seen in FIG. 1, the vacuum head 100 includes a vacuum housing 110 with wheels 112 that move along the surfaces of the pool. A catch bag 120 is secured to a top open end 116 of the housing, at the top of a thrust channel 118 that extends from the bottom mouth 114 of the vacuum head housing to the top end 116. The bottom end 114 is where the dirt, leaves, grass, weeds and other debris are picked up by the pool vacuum, as seen in FIG. 1. To create a force of thrust from the open mouth 114 and up through the thrust channel 118 and into the catch bag 120, thereby pulling the debris up from the surfaces of the pool and through the open mouth 114 of the vacuum head and into the catch bag 120, a propeller 10 is rotated by an electric motor 130 that is secured to the vacuum head housing within the thrust channel. As seen in FIGS. 1 and 2, the propeller 10 is maintained near the top end 116 of the thrust channel 118 and is rotated by the electric motor 130 creating the upward thrust force, as indicated by the arrows in FIG. 2.

The propeller 10 includes a hub 20 having a first end 22 and an opposite second end 24, and an outer cylindrical surface 26 extending between the first and second ends. The propeller 10 further includes at least two blades 30 extending axially outward from the outer cylindrical surface 26, on opposite sides of the hub 20, as clearly seen in the several views of the drawings. Naturally, the blades 30 of the propeller 10 are shaped and pitched to create the desired force of thrust at predetermined speeds of rotation without creating cavitation.

The hub 20 of the propeller 10 has a central axial bore 34 that may be supported by webs 35 or other structure extending inward from the hub. The central axial bore 34 is specifically sized and positioned for receipt of an output shaft 134 of the electric motor 130. In at least one embodiment, the output shaft 134 includes screw threads 136 to allow for secured attachment of the propeller 10 on the output shaft with the use of a washer 36 and nut 38. In a preferred embodiment, the washer 36 is specifically sized and configured for receipt within the open central area 32 of the hub 20 and includes a hex-shaped receptacle 37 for secured receipt of the nut 38 therein so that the nut is not able to freely rotate and become loose during operation of the electric motor 130 and rotation of the output shaft 134.

The propeller 10 of the present invention is specifically designed to prevent debris, such as grass, weeds and other stringy items from being entangled around the base of the output shaft, between the end 132 of the motor housing and the first end 22 of the hub 20. To achieve this purpose, the hub 20 is provided with a number of discharge channels 40 that extend from the first end 22 of the hub 20 to the opposite second end 24 of the hub. Each of the discharge channels 40 is open at the first end 22, as well as the opposite second end 24, and provides an unobstructed passage therethrough from the first end 22 to the opposite second end 24. As seen in FIGS. 2-4, the discharge channels 40 are arranged about the circumference of the hub 20 in close, spaced relation to one another. The discharge channels 40 may be oblong or oval in shape, as seen in FIGS. 2-4, or of any other general cross-sectional configuration such as circular. In operation, as the propeller 10 is rotated underwater by the electric motor 130, a force of thrust is created, as seen by the arrows in FIG. 2, and some water does enter between the hub 20 of the propeller and the top end 132 of the electric motor. Normally, this water would be momentarily trapped between the hub 20 and the propeller 10 and all debris within the waterflow would be directed towards the output shaft 134. Naturally, long, stringy debris, such as grass and weeds, would become entangled about the base of the output shaft 134. However, the discharge channels 40 extending through the hub 20 of the propeller of the present invention are specifically designed to direct water that enters between the propeller hub 10 and the top end 132 of the electric motor housing 130 through the discharge channels 40 prior to reaching the output shaft 134. This directed flow of water through the discharge channels 40 carries any debris, including grass, weeds and other stringy items, through the discharge channels for exit out from the top of the discharge channels 40 at the second end 24 of the hub, at which point the debris is picked up by the force of thrust created by the rotating propeller blades 30, allowing the debris to be moved into the catch bag of the submersible pool vacuum head.

As seen in FIGS. 3 and 5, a pin 50 is received through the output shaft 134, in spaced relation from the top end 132 of the motor housing. The first end 22 of the hub 20 of the propeller includes a slot 54 that receives the transverse pin 50 therein, serving to limit movement of the hub 20 downwardly onto the output shaft 134, thus serving as a stop member so that the first end 22 of the hub does not engage the top end 132 of the motor housing. The transverse pin 50 which is received within the slot 54 formed in the hub also discourages rotation of the hub 20 relative to the output shaft 134.

Since many modifications, variations and changes in detail can be made to the described embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents. 

What is claimed is:
 1. A propeller for attachment to a rotatable output shaft of a submersible motor comprising: a hub including a first end, an opposite second end, an outer curved surface between the first and second ends, and a central axial bore for receipt of the output shaft therethrough; at least two blades extending radially outward from the outer curved surface of the hub; and a plurality of discharge channels extending from the first end to the second end of the hub, and each of the plurality of discharge channels being open at the first and second ends of the hub and having an unobstructed passage therethrough, and each of the plurality of discharge channels being structured and disposed to direct waterflow and debris therethrough from the first end and exiting the second end of the hub to avoid becoming entangled around the output shaft during operation of the motor and propeller, wherein the propeller is drivingly rotated by the output shaft.
 2. The propeller as recited in claim 1 wherein the outer curved surface of the hub is cylindrical.
 3. The propeller as recited in claim 1 wherein the hub further includes an inner curved surface concentric with the outer curved surface.
 4. The propeller as recited in claim 3 wherein the plurality of discharge channels extend from the first end to the second end of the hub and between the outer curved surface and the inner curved surface.
 5. The propeller as recited in claim 1 further comprising: a stop pin fitted transversely through the output shaft; and a transverse slot formed in the hub for receiving the stop pin and limiting axial movement of the hub on the output shaft towards the motor, thereby preventing the hub from contacting the motor.
 6. The propeller as recited in claim 1 wherein each of the plurality of discharge channels has an oval cross-sectional configuration.
 7. The propeller as recited in claim 6 wherein the transverse cross-sectional configuration of each of the plurality of discharge channels is uniform along the length of each of the plurality of discharge channels from the first end to the second end of the hub. 